dmolony-DiskBrowser/src/com/bytezone/diskbrowser/applefile/SourceLine.java

package com.bytezone.diskbrowser.applefile;

import static com.bytezone.diskbrowser.utilities.Utility.unsignedShort;

import java.util.ArrayList;
import java.util.List;

import com.bytezone.diskbrowser.utilities.Utility;

// -----------------------------------------------------------------------------------//
public class SourceLine implements ApplesoftConstants
// -----------------------------------------------------------------------------------//
{
  ApplesoftBasicProgram parent;
  int linkField;
  int lineNumber;
  int linePtr;
  int length;
  byte[] buffer;

  List<SubLine> sublines = new ArrayList<> ();

  // ---------------------------------------------------------------------------------//
  SourceLine (ApplesoftBasicProgram parent, byte[] buffer, int ptr)
  // ---------------------------------------------------------------------------------//
  {
    this.parent = parent;
    this.buffer = buffer;

    linePtr = ptr;
    linkField = unsignedShort (buffer, ptr);
    lineNumber = unsignedShort (buffer, ptr + 2);

    int startPtr = ptr += 4;              // skip link to next line and lineNumber
    boolean inString = false;             // can toggle
    boolean inRemark = false;             // can only go false -> true
    byte b;

    while (ptr < buffer.length && (b = buffer[ptr++]) != 0)
    {
      if (inRemark)                       // cannot terminate a REM
        continue;

      if (inString)
      {
        if (b == Utility.ASCII_QUOTE)           // terminate string
          inString = false;
        continue;
      }

      switch (b)
      {
        // break IF statements into two sublines (allows for easier line indenting)
        case ApplesoftConstants.TOKEN_IF:
          // skip to THEN or GOTO - if not found then it's an error
          while (buffer[ptr] != TOKEN_THEN && buffer[ptr] != TOKEN_GOTO
              && buffer[ptr] != 0)
            ptr++;

          // keep THEN with the IF
          if (buffer[ptr] == TOKEN_THEN)
            ++ptr;

          // create subline from the condition (plus THEN if it exists)
          sublines.add (new SubLine (this, startPtr, ptr - startPtr));
          startPtr = ptr;
          break;

        // end of subline, so add it, advance startPtr and continue
        case Utility.ASCII_COLON:
          sublines.add (new SubLine (this, startPtr, ptr - startPtr));
          startPtr = ptr;
          break;

        case TOKEN_REM:
          if (ptr == startPtr + 1)
            inRemark = true;
          else
          {     // REM appears mid-line (should follow a colon)
            System.out.printf ("%5d %s%n", lineNumber, "mid-line REM token");
            ptr--;            // point back to this REM
            sublines.add (new SubLine (this, startPtr, ptr - startPtr));
            startPtr = ptr;
          }
          break;

        case Utility.ASCII_QUOTE:
          inString = true;
          break;
      }
    }

    length = ptr - linePtr;

    // add whatever is left after the last colon
    // if no colon was found this is the entire line
    int bytesLeft = ptr - startPtr;
    sublines.add (new SubLine (this, startPtr, bytesLeft));
  }
}